If you've ever been alarmed to find oddly-shaped red patches on your tongue, you can relax for the most part. Most likely, you're part of a small fraction of the population with a condition known as geographic tongue.

The name comes from the irregular shape of the patches that seem to resemble land formations on a map. Its medical name is benign migratory glossitis, which actually describes a lot about the condition. The patches are actually areas of inflammation on the tongue (“glossus” – tongue; “itis” – swelling) that appear to move around or migrate. They're actually made up of areas where the tiny bumps (papillae) you normally feel have disappeared: the patches feel flat and smooth compared to the rest of the tongue.

We're not sure why geographic tongue occurs. It often runs in families and seems to occur mostly in middle-aged adults, particularly women and non-smokers. It's believed to have a number of triggers like emotional stress, hormonal disturbances or vitamin or mineral deficiencies. There may also be a link between it and the skin condition psoriasis. Under a microscope the red patchiness of both appears to be very similar in pattern; the two conditions often appear together.

The bad news is we can't cure geographic tongue. But the good news is the condition is benign, meaning it's not cancerous; it's also not contagious. It poses no real health threat, although outbreaks can be uncomfortable causing your tongue to feel a little sensitive to the touch with a burning or stinging sensation. Some people may also experience numbness.

Although we can't make geographic tongue go away permanently, you should come by for an examination to confirm that is the correct diagnosis. Once we know for sure that you do have migratory glossitis, we can effectively manage discomfort when it flares up. You should limit your intake of foods with high acidity like tomatoes or citrus fruits, as well as astringents like alcohol or certain mouthrinses. We can also prescribe anesthetic mouthrinses, antihistamines or steroid ointments if the discomfort becomes more bothersome.

It may look strange, but geographic tongue is harmless. With the right care it can be nothing more than a minor annoyance.